下表资料摘自联合国于2000年发布的预测报告，反映了2001～2050年世界移民趋势。据此完成下列问题题。                      

阅读理解。

生命的本质

       夜幕降临，对门那家又传出熟悉的和生疏的音乐，响起时紧时缓的舞蹈脚步。

       那是一对才搬来的残疾夫妻，男的一双脚掌向后撇，女的是哑巴。那天初次见到他们时，一股怜悯之情在我心头升起；这样的人生，这样的家庭，该怎样艰难！这不是我鄙视他们，我认为作为一个正常人，是应该有一点这样的怜悯之心的。

       但接下来的事实让我大吃一惊，这些天来，他们的那些残疾人朋友络绎在夜幕之后前来集会，空气里传来他们的音乐、舞蹈和欢笑。我看不到他们的表情，但我可以感觉到他们的舞蹈火一般忘情、热烈。

       面对着这样的一群人，我感到世上所有的词汇变得苍白、不贴切。说残疾人也爱生活，也需要音乐和舞蹈．这样的解释是那么的无力、词不达意。只有用火的舞蹈，才恰如其分。火在舞蹈，那扭动、变形的舞姿是火的生命张力的表达。燃体在火的舞蹈中发出毕毕剥剥的吟唱，燃体不尽，火的舞蹈不停。

       熟悉的和陌生的音乐像一支焰火，一下子照亮了我记忆的天空。我透过遥远岁月重又看到生命在另一种形式下的舞蹈：那是在一座简陋的砖瓦窑，我三十年前下放劳动的地方。窑师傅的小女儿才七八岁，就 开始帮大人做事了。这个小姑娘一身衣服缀满补丁,正当读书和游戏的年龄，就过早地承担了生活的艰辛。当时我也以怜悯的目光注视这个小女孩，但艰辛的劳动在小女孩身上却成了舞蹈，她蹦蹦跳跳，舞着工具，全无一点悲愁。她一下子就让我陷入对生命的沉思和叩问：生命的本质是什么？是什么让生命以这 样欢乐的形式前行的？

       用童心无邪，用不谙世事，用乐观主义来解释都是不够的。上苍仿佛有意安排，让我看到不同形式的两次生命的舞蹈。生命从一降生，就穿上了一双红舞鞋。这是生命的本质，是人在任何艰难困苦的情况下都会歌唱、都会欢乐的原因。

       人类的生命史穿越了数千年，其间战争、灾难、病痛、死亡都阻挡不了生命欢乐的舞蹈，废墟上一次又一次出现辉煌的殿宇。灾难之后，人类又一代代繁衍生息。没有畏惧，从不悲观，生命就这样一路舞着唱着前行，这一切都因为生命的本质就是舞蹈。

C

    When Matty Sallin，34，was working on a degree in art and technology at New York University，he got interesting homework in electronics class．He decided to create an alarm clock(闹钟)．

    "Everybody has to deal with these every day，and they are really unpleasant!"he says．He asked different people what they would like to wake up to instead of a noisy alarm．A lot of them said，"The smell of bacon(培根肉)"．

    So Sallin and two classmates invented a new kind of alarm clock：a wooden box with a pig face and a digital clock that uses the smell of cooking bacon instead of the sound to wake someone up．He explains．"There's no danger of burning，because I built it carefully．It uses halogen light bulbs(卤素灯)instead of a fire for cooking and turns off automatically after ten minutes．Yes,the clock itself can do it．Just a few easy steps are needed to set the alarm．"

    "What you do is to put some frozen bacon in the night before and set the alarm，"says Sallin．

    "If you set the alarm for 8：00,it will turn on at 7：50 and slow cook for ten minutes under the halogen bulbs．"he says，Then the bulbs turn off and a fan blows the smell out through the nose of the pig．

    "So instead of an alarm，  ▲，"says Sallin．"Then you can open the door on the side and pull the bacon out and eat it．"

    When Sallin was a kid，he spent a lot of time making drawing of inventions．"I wanted to make an lift in my backyard and a special tree house．"he says．"But I never really thought I'd be called an inventor!"

    Sallin got an A in the class and went on to other things—but people continue to hear about his invention and email him every day asking where they can buy his alarm clock．

已知实数a、b满足ab=1，a+b=2，求代数式a²b+ab²的值．